how to integrate login system of gmail in my application?

Question

I am developing a web application where users can sign in with their id, or facebook id, twitter id or gmail id. I have done this with facebook and twitter so far. But I am running into problems with gmail. In facebook and twitter case, I have created an application going to developers/..../new/app like this and get appid for both facebook and twitter, and integrated both in my login system, but in case of gmail I'm confused. Is there any process/thing, I mentioned above in case of gmail a/c?

I am doing my project in PHP CodeIgniter.

Answer 1

This is called Authentication Federation, and Google documents it in their Google Developers site. In summary, they support OpenID:

https://developers.google.com/accounts/docs/OpenID